Hybrid torque tube

ABSTRACT

A hybrid torque tube for a brake assembly may comprise a tube portion having a centerline axis, and a conical back-leg portion extending from the tube portion. A stator spline may be formed on a radially outward surface of the tube portion. A foot may be formed on a radially inward surface of the tube portion. The tube portion is formed using a first manufacturing process and at least one of the conical back-leg, stator spline, or foot is formed using additive manufacturing.

FIELD

The present disclosure relates to brake systems, and more specifically,to torque tubes for aircraft brake systems.

BACKGROUND

Aircraft typically have brakes on the wheels to slow the aircraft duringaborted takeoffs, landings, and while taxiing. Aircraft brake systemsgenerally employ a brake stack comprised of a series of friction disks,which may be forced into contact with one another to stop the aircraft.The brake systems may include a torque tube (also referred to as atorque plate). The torque tube is generally machined from a single pieceof metal which tends to generate a large amount of material waste andwhich forms a solid metal torque tube with increased weight.

SUMMARY

In various embodiments, the present disclosure provides a method ofmaking a hybrid torque tube for a brake assembly. The method maycomprise forming a tube portion having a centerline axis using a firstmanufacturing process, forming and a conical back-leg extending from thetube portion in a radially outward angled orientation relative to thecenterline axis, forming a stator spline on a radially outward surfaceof the tube portion, and forming a foot extending from a radially inwardsurface of the tube portion. At least one of the conical back-leg, thestator spline, or the foot may be formed using a second manufacturingprocess different from the first manufacturing process. The secondmanufacturing process may comprise an additive manufacturing technique.

In various embodiments, a portion of the stator spline may be hollow. Invarious embodiments, a cross-section of the stator spline may comprise alattice structure. In various embodiments, forming the stator spline maycomprise depositing a base material with a coating located over the basematerial.

In various embodiments, the method may further comprise forming the tubeportion using a first metal alloy, and forming, at least, a portion ofthe conical back-leg using a second metal alloy different from the firstmetal alloy.

In various embodiments, the method may further comprise forming the tubeportion using a first metal alloy, and forming the foot using a secondmetal alloy different from the first metal alloy. The second metal alloymay comprise a greater resistance to creep as compared to the firstmetal alloy.

Also disclosed herein, according to various embodiments, is a method ofmaking a hybrid torque tube for a brake assembly comprising forming atube portion having a centerline axis using a first manufacturingprocess, forming a conical back-leg extending from a first end of thetube portion, forming a flange at a second end of the tube portionopposite the first end of the tube portion, forming a foot extendingfrom a radially inward surface of the tube portion, and forming a statorspline on the tube portion. At least one of the conical back-leg, theflange, the foot, or the stator spline may be formed using a secondmanufacturing process. The second manufacturing process may comprise anadditive manufacturing technique.

In various embodiments, the first manufacturing process may comprise atleast one of forging, extrusion, casting, machining, stamping, orsubtractive manufacturing. In various embodiments, the flange, the foot,or the stator spline may be formed using the second manufacturingprocess, and the conical back-leg may be formed using at least one offorging, extrusion, casting, machining, stamping, subtractivemanufacturing, welding, or swaging.

In various embodiments, forming the stator spline may comprisedepositing a base material with a wear coating located over the basematerial. In various embodiments, a portion of the stator spline may behollow.

In various embodiments, the tube portion may comprise a first materialand the foot may comprise a second material different from the firstmaterial.

Also disclosed herein, according to various embodiments, is a hybridtorque tube for a brake assembly. The hybrid torque tube may comprise atube portion having a centerline axis. The tube portion may comprise afirst metal alloy. A conical back-leg may extend from the tube portionin a radially outward angled orientation relative to the centerlineaxis. A stator spline may be formed on a radially outward surface of thetube portion. A foot may be formed on a radially inward surface of thetube portion. At least one of the conical back-leg, the stator spline,or the foot may comprise a second metal alloy different from the firstmetal alloy.

In various embodiments, a portion of the stator spline is hollow. Invarious embodiments, a portion of the stator spline comprises a latticestructure. In various embodiments, an end of the stator spline proximatethe conical back-leg may be tapered.

In various embodiments, the first metal alloy may comprise a firstnon-ferrous material, and the second metal alloy may comprise a secondnon-ferrous material different from the first non-ferrous material. Thesecond non-ferrous material may have a greater resistance to creep ascompared to the first non-ferrous material. In various embodiments, thefirst metal alloy may comprise, by weight, 6% aluminum, 4% vanadium, amaximum of 0.2% oxygen, a maximum of 0.25% iron, and at least 89%titanium. The second metal alloy may comprise, by weight, 6% aluminum,2% tin, 4% zirconium, 2% molybdenum, and at least 85% titanium.

In various embodiments, the first metal alloy may comprise a firstferrous material, and the second metal alloy may comprise a secondferrous material different from the first ferrous material.

The forgoing features and elements may be combined in variouscombinations without exclusivity, unless expressly indicated hereinotherwise. These features and elements as well as the operation of thedisclosed embodiments will become more apparent in light of thefollowing description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a cross-sectional view of a brake assembly, inaccordance with various embodiments;

FIG. 2A illustrates a cutaway of a hybrid torque tube, in accordancewith various embodiments;

FIG. 2B illustrates a cross-sectional view of a portion of a hybridtorque tube having a conical back-leg formed by additive manufacturing,in accordance with various embodiments;

FIGS. 3A and 3B illustrate, respectively, a perspective view and across-sectional view of a hollow stator spline, in accordance withvarious embodiments;

FIG. 3C illustrates a perspective view of a stator spline havingmultiple hollow portions, in accordance with various embodiments;

FIG. 3D illustrates a perspective view of a stator spline havingportions comprised of different materials, in accordance with variousembodiments;

FIGS. 3E and 3F illustrate, respectively, a perspective view and across-sectional view of a stator spline comprising a lattice structure,in accordance with various embodiments;

FIGS. 3G and 3H illustrate, respectively, a perspective view and across-sectional view of a stator spline having a wear coating, inaccordance with various embodiments; and

FIGS. 4A and 4B illustrate a method of making a hybrid torque tube, inaccordance with various embodiments.

The subject matter of the present disclosure is particularly pointed outand distinctly claimed in the concluding portion of the specification. Amore complete understanding of the present disclosure, however, may bestbe obtained by referring to the detailed description and claims whenconsidered in connection with the drawing figures, wherein like numeralsdenote like elements.

DETAILED DESCRIPTION

The detailed description of exemplary embodiments herein makes referenceto the accompanying drawings, which show exemplary embodiments by way ofillustration. While these exemplary embodiments are described insufficient detail to enable those skilled in the art to practice theexemplary embodiments of the disclosure, it should be understood thatother embodiments may be realized and that logical changes andadaptations in design and construction may be made in accordance withthis disclosure and the teachings herein without departing from thespirit and scope of the disclosure. Thus, the detailed descriptionherein is presented for purposes of illustration only and not oflimitation.

Surface cross hatching lines may be used throughout the figures todenote different parts but not necessarily to denote the same ordifferent materials. Throughout the present disclosure, like referencenumbers denote like elements. Accordingly, elements with like elementnumbering may be shown in the figures, but may not be necessarily berepeated herein for the sake of clarity.

As used herein, a first component that is “radially outward” of a secondcomponent means that the first component is positioned at a greaterdistance away from a common axis than the second component. A firstcomponent that is “radially inward” of a second component means that thefirst component is positioned closer to the common axis than the secondcomponent. In the case of components that rotate circumferentially abouta common axis, a first component that is radially inward of a secondcomponent rotates through a circumferentially shorter path than thesecond component. As used herein, “distal” refers to the directionoutward, or generally, away from a reference component. As used herein,“proximal” and/or “proximate” refer(s) to a direction inward, orgenerally, towards the reference component.

With reference to FIG. 1, a multi-disk brake system 20 is illustrated,in accordance with various embodiments. An A-R-C axis has been includedin the drawings to illustrate the axial (A), radial (R) andcircumferential (C) directions. Multi-disk brake system 20 may include awheel 10 supported for rotation around axle 12 by bearings 14. Wheel 10includes rims 16 for supporting a tire, and a series of axiallyextending rotor splines 18 (one shown). Rotation of wheel 10 ismodulated by multi-disk brake system 20. Multi-disk brake system 20includes a piston housing 22, torque tube 24, a plurality of pistons 26(one shown), pressure plate 30, end plate 32, and plurality of frictiondisks 38 located between pressure plate 30 and end plate 32.

The plurality of friction disks 38 includes at least one non-rotatablefriction disk 40, also known as a stator, and at least one rotatablefriction disk 42, also known as a rotor. Each of the friction disks 38includes an attachment structure. In various embodiments, each of thefour non-rotatable friction disks 40 includes a plurality of stator lugs44 at circumferentially spaced positions around the non-rotatablefriction disk 40 as an attachment structure. Similarly, each of the fiverotatable friction disks 42 includes a plurality of rotor lugs 46 atcircumferentially spaced positions around the rotatable friction disk 42as an attachment structure. Pressure plate 30, end plate 32, andfriction disks 38 are each annular structures and may be made at leastpartially from a carbon composite material.

With reference to FIG. 2A, torque tube 24 is an elongated annularstructure that includes a cylindrical tube portion 100 having acenterline axis 102, a conical back-leg 104 (also referred to as apressure flange web) extending from tube portion 100, and a series ofaxially extending stator splines 106 (also referred to as torque lugs)formed on a radially outward surface, or outer diameter, 108 of tubeportion 100. The conical back-leg 104 extends radially outward from tubeportion 100 and towards wheel 10 at an angled orientation relative tocenterline axis 102. In various embodiments, conical back-leg 104 has afrustoconical shape. Torque tube 24 may further include a flange 110(also referred to as a piston housing flange) and a foot 112 (alsoreferred to as an inner support flange). Flange 110 may be formed at anend of tube portion 100 that is opposite conical back-leg 104. Flange110 may extend radially inward from tube portion 100. Flange 110 may becoupled to piston housing 22, with momentary reference to FIG. 1, via afastener 111. Fastener 111 may comprise a screw, bolt, rivet, pin, orother suitable securement mechanism.

Returning to FIG. 2A, foot 112 may be formed on a radially inwardsurface, or inner diameter, 114 of tube portion 100. Foot 112 maycontact an axle 12, with momentary reference to FIG. 1. In variousembodiments, a lip 116 may be formed on a radially outward end ofconical back-leg 104. Lip 116 may extend axially from conical back-leg104 such that lip 116 is parallel radially outward surface 108 of tubeportion 100. In various embodiments, lip 116 may be oriented at angle ofup to 90° relative to a plane parallel with radially outward surface 108of tube portion 100.

As discussed in further detail below, torque tube 24 is hybrid torquetube. As used herein, a “hybrid torque tube” refers to a torque tubehaving at least one component (e.g., stator splines 106, flange 110,foot 112, lip 116, etc.) formed using an additive manufacturingtechnique, for example, wire arc additive manufacturing or electron beamadditive manufacturing, and at least one component (e.g., tube portion100) formed using a non-additive manufacturing technique, for example,forging, extrusion, machining, casting, stamping, or subtractivemanufacturing.

Returning to FIG. 1, piston housing 22 is mounted to axle 12. Flange 110of torque tube 24 is bolted or otherwise coupled to piston housing 22with conical back-leg 104 of torque tube 24 proximate an axial center ofwheel 10. End plate 32 is connected or mounted to lip 116 of torque tube24. In various embodiments, lip 116 may define one or more holesextending through lip 116 and configured to receive a fastener 120.Fastener 120 may comprise a bolt, pin, anchor, lug, or other suitablesecurement mechanism. Stator splines 106 support non-rotatable frictiondisks 40. Stator splines 106 may also support pressure plate 30 suchthat pressure plate 30 is also non-rotatable. Non-rotatable frictiondisks 40 engage stator splines 106 via gaps formed between stator lugs44. Similarly, rotatable friction disks 42 engage rotor splines 18 viagaps formed between rotor lugs 46. Rotatable friction disks 42 arerotatable by virtue of their engagement with rotor splines 18 of wheel10.

Rotatable friction disks 42 are arranged with end plate 32 on an endproximate wheel 10, with pressure plate 30 on an end distal wheel 10 andproximate pistons 26, and with non-rotatable friction disks 40interleaved so that rotatable friction disks 42 are adjacent tonon-rotatable friction components (e.g., interleaved rotors andstators). Pistons 26 are connected to piston housing 22 atcircumferentially spaced positions around piston housing 22. Pistons 26face axially toward wheel 10 and contact a side of pressure plate 30opposite rotatable friction disks 42. Pistons 26 may be poweredelectrically, hydraulically, or pneumatically.

In various embodiments, in response to actuation of pistons 26, a forceis exerted on the rotatable friction disks 42 and the non-rotatablefriction disks 40 towards conical back-leg 104. The rotatable frictiondisks 42 and the non-rotatable friction disks 40 may thus be pressedtogether between pressure plate 30 and end plate 32.

Under various braking conditions, a large amount of torque may beapplied to friction disks 38 and an extreme amount of heat may begenerated. In this regard, various components and/or areas of torquetube 24 may experience increased mechanical stresses at elevatedtemperatures, which may cause these components and/or areas to “creep.”Stated differently, the mechanical stresses and increased heat generatedduring various braking events may lead to deformation of one or morecomponents of torque tube 24. The present disclosure, according tovarious embodiments, provides a hybrid torque tube which is both lightweight and resistant to creep. More specifically, and according tovarious embodiments, a hybrid torque tube may be manufactured using bothadditive and non-additive manufacturing techniques whereby thecomponents and/or areas of the torque tube that are more susceptible tocreep may be formed using materials that have an increased creepresistance, while other components and/or areas of the torque tube thatare less susceptible to creep may be formed using other less creepresistant materials. Minimizing and/or reducing the amount of materialhaving increased creep resistance tends to reduce manufacturing costs.Additionally, employing additive manufacturing techniques to formvarious components of the torque tube tends to decrease material wasteand allow for geometries that may not otherwise be possible with othermanufacturing processes.

Referring to FIG. 2A, tube portion 100 of torque tube 24 may be formedusing a first manufacturing process which employs non-additivemanufacturing techniques. For example, tube portion 100 may be formed byforging, extrusion, machining, casting, stamping, subtractivemanufacturing, and/or other suitable non-additive manufacturingtechniques. Tube portion 100 may comprise a non-ferrous material, forexample, titanium or titanium alloy. In various embodiments, tubeportion 100 may comprise a titanium alloy conforming to the unifiednumbering system standard (UNS) R56400, also referred to as Grade 5titanium, which may also be referred to as Ti-6Al-4V (Ti64), and whichis comprised of, by weight, 6% aluminum, 4% vanadium, a maximum of 0.2%Oxygen, a maximum of 0.25% iron, and at least 89% titanium. In variousembodiments, tube portion 100 may comprise a ferrous material, forexample, a chromium-molybdenum steel, a nickel-chromium-molybdenumsteel, or a nickel-chromium-molybdenum-vanadium steel.

Stator splines 106 may be formed on radially outward surface 108 of tubeportion 100 using a second manufacturing process that employs anadditive manufacturing technique. For example, tube portion 100 may beformed by forging, extrusion, casting, and/or machining, and statorsplines 106 may be formed by wire arc additive manufacturing, electronbeam additive manufacturing, or other suitable additive manufacturingtechnique. Forming stator splines 106 using additive manufacturingallows the geometries and materials of stator splines 106 to be uniquelytailored.

FIG. 3A illustrates a perspective view of a stator spline 106, inaccordance with various embodiments. FIG. 3B illustrates across-sectional view of stator spline 106 taken along the line 3B-3B inFIG. 3A and generally parallel to the R-axis in FIG. 1. In variousembodiments, additive manufacturing may be employed to form statorspline 106 having a hollow portion. In various embodiments, statorspline 106 may be formed by depositing a material 128, for example, ametal or metal alloy, on radially outward surface 108 of torque tube 24using, for example, wire arc or electron beam additive manufacturing.Stator spline 106 comprises an internal portion or cavity 130 that isdevoid of material 128. Stated differently, material 128 defines aninternal cavity 130 within stator spline 106. While FIGS. 3A and 3Billustrate internal cavity 130 having a square or rectangularcross-sectional geometry, it should be understood that internal cavity130 may be formed having a cross-sectional geometry that is circular,oval, triangular, polygonal, or any other shape.

With combined reference to FIG. 2A and FIG. 3C, in various embodiments,torque tube 24 may be formed having one or more stator splines 136 withmultiple hollow portions. Stator spline(s) 136 may be formed on tubeportion 100 using additive manufacturing. In various embodiments, amaterial 138, for example, a metal or metal alloy, is deposited onradially outward surface 108 of tube portion 100 using wire arc orelectron beam additive manufacturing to form stator spline 136. Statorspline 136 comprises a plurality of internal portions or cavities 140that are devoid of material 138. Stated differently, material 138defines a plurality of internal cavities 140 within stator spline 136.While FIG. 3C illustrates internal cavities 140 having a square orrectangular cross-sectional geometry, it should be understood thatinternal cavities 140 may be formed having a cross-sectional geometrythat is circular, oval, triangular, polygonal, or any other shape. Invarious embodiments, a first hollow portion 142 of stator spline 136 maycomprise a cross-sectional geometry that is different from thecross-sectional geometry of a second hollow portion 144 of stator spline136. The stator splines on tube portion 100 may comprise any mix ofhollow splines and non-hollow splines in any type of arrangement. Thestator splines may be arranged to allow directional heat flow to leavethe wheel or may provide alternative type of cooling paths, as heatdissipation from the hollow stator splines will differ from heatdissipation from solid stator splines.

With combined reference to FIG. 2A and FIG. 3D, in various embodiments,torque tube 24 may be formed having one or more stator splines 146 withportions of varying material. Stator spline(s) 146 may be formed on tubeportion 100 using additive manufacturing. In various embodiments, afirst portion 148 of stator spline 146 may be formed by depositing ametal or metal alloy 154 on radially outward surface 108 using wire arcor electron beam additive manufacturing. A second portion 150 of statorspline 146 may be formed by depositing a metal or metal alloy 156, whichis different from the metal or metal alloy 154, on radially outwardsurface 108 using wire arc or electron beam additive manufacturing. Invarious embodiments, first portion 148 may comprise a material having agreater heat resistance (i.e., higher melting point), a greater tensilestrength, and/or a greater creep resistance as compared to the materialof second portion 150. In various embodiments, first portion 148 maycomprise a material having a different thermal conductivity as comparedto the material of second portion 150 to provide variable heatconduction during braking. A third portion 152 of stator spline 146 maybe formed by depositing a metal or metal alloy 158, which is differentfrom metal or metal alloy 156, on radially outward surface 108 usingwire arc or electron beam additive manufacturing. Metal or metal alloy158 may be the same or different from metal or metal alloy 154. Invarious embodiment, the transition between first portion 148 and secondportion 150 and/or the transition between second portion 150 and thirdportion 152 may be a gradient transition. While stator spline 146 isshown having axially adjacent portions 148, 150, and 152 comprised ofvarying materials, it should be understood that stator spline 146 may beformed having radially adjacent, circumferentially adjacent, and/ordiagonally adjacent portions of varying materials.

FIG. 3E illustrates a perspective view of a stator spline 166 having alattice structure, in accordance with various embodiments. FIG. 3Fillustrates a cross-sectional view of stator spline 166 taken along theline 3F-3F in FIG. 3E and generally parallel to the R-axis shown inFIG. 1. With combined reference to FIG. 2A and FIGS. 3E and 3F, invarious embodiments, torque tube 24 may be formed having one or morestator splines 166 comprised of a lattice structure. Stator spline(s)166 may be formed on tube portion 100 using additive manufacturing. Invarious embodiments, a material 168, for example, a metal or metalalloy, may be deposited on radially outward surface 108 of tube portion100 using wire arc or electron beam additive manufacturing to form thelattice structure of stator spline 166. While stator spline 166 is shownhaving a lattice structure with square or diamond shape openings definedby material 168, it should be understood that stator spline 166 may havea lattice structure of any geometry, for example, in variousembodiments, material 168 may define honeycomb-shaped openings. WhileFIG. 3F illustrates a cross-sectional view of stator spline 166 takenalong a radial plane (i.e., along a plane parallel to the R-axis in FIG.1), in various embodiments, a cross-section of stator spline 166 takenalong an axial plane (i.e., a plane parallel to the A-axis in FIG. 1)may comprise a lattice structure.

FIG. 3G illustrates a perspective view of a stator spline 176 having awear coating, in accordance with various embodiments. FIG. 3Hillustrates a cross-sectional view of stator spline 176 taken along theline 3H-3H in FIG. 3G and generally parallel to the R-axis shown inFIG. 1. With combined reference to FIG. 2A and FIGS. 3G and 3H, invarious embodiments, torque tube 24 may be formed having one or morestator spline(s) 176 including a coating 180. Stator spline 176 maycomprise a base material 178, for example, a titanium-based alloy, and acoating 180, for example, a nickel-based superalloy, located over thebase material 178. Stator spline(s) 176 may be formed on tube portion100 using additive manufacturing. In this regard, base material 178 andcoating 180 located over base material 178 may be deposited using wirearc or electron beam additive manufacturing. In various embodiments,coating 180 may be located over some portions of base material 178 andother portions of base material 178 may be devoid of coating 180. Forexample, the portions having coating 180 may correspond to portions ofstator spline 176 that engage stator lugs 44, with momentary referenceto FIG. 1. Coating 180 may comprise a wear resistance coating, a thermalresistance coating, a corrosion resistance coating, or a combination oftwo or more type coatings.

Returning to FIG. 2A, in various embodiments, foot 112 may be formed onradially inward surface 114 of tube portion 100 using additivemanufacturing. Forming foot 112 using additive manufacturing may allow,at least, a portion of foot 112 to be formed using a material having agreater resistance to creep as compared to other components of torquetube 24. For example, in various embodiments, tube portion 100 may beformed using Ti64 and foot 112 may be formed using a titanium alloyconforming to UNS R54620, which may be referred to as Ti-6Al-2Sn-4Zr-2Mo(Ti6242), and which is comprised of, by weight, 6% aluminum, 2% tin, 4%zirconium, 2% molybdenum, and at least 85% titanium. In variousembodiments, foot 112 may be formed using a titanium alloy conforming toUNS R54620, which may be referred to as Ti-6Al-2Sn-4Zr-2Mo-0.08Si(Ti6242S), and which is comprised of, by weight, 6% aluminum, 2% tin, 4%zirconium, 2% molybdenum, 0.08% silicon, and at least 85% titanium, orusing any other near-alpha, alpha, or alpha+beta titanium alloy.

In various embodiments, one or more components of torque tube 24 maycomprise a nickel based superalloy. For example, in various embodiments,one or more components of torque tube 24 may be formed using a nickelbased superalloy conforming to UNS N07718, which is comprised of, byweight, 50%-55% nickel (plus cobalt), 17%-21% chromium, 2.8%-3.3%molybdenum, 4.75%-5.5% niobium (plus tantalum), 0.65%-1.15% titanium,0.2%-0.8% aluminum, and a max of 1% cobalt.

In various embodiments, tube portion 100 may be formed using a ferrousmaterial (e.g., a chromium-molybdenum steel or anickel-chromium-molybdenum steel) and foot 112 may be formed using aferrous material this different from the ferrous material of tubeportion 100. In various embodiments, the ferrous material of foot 112may comprise a greater resistance to creep, as compared to the ferrousmaterial of tube portion 100.

Forming foot 112 using additive manufacturing also allows differentportions of foot 112 to be formed using different materials. Forexample, a radially extending portion 112 a of foot 112 may comprise amaterial having a greater heat resistance (i.e., higher melting point),tensile strength, and/or creep resistance as compared to the materialused to form an axially extending portion 112 b of foot 112. Withcombined reference to FIG. 1 and FIG. 2A, in various embodiments, foot112 may be formed using a material that provides thermal insulation, forexample, a material having a decreased thermal conductivity as comparedto a material of tube portion 100, in order to reduce conduction of heatto axle 12. In various embodiments, foot 112 may comprise a latticestructure configured to reduce conduction of heat to axle 12.Configuring foot 112 to better insulate axle 12 from heat generated byfriction disks 38 may allow other types of insulators located betweenfoot 112 and axle to be removed.

In various embodiments, flange 110 and/or lip 116 may also be formedusing additive manufacturing and may each comprise a material that isdifferent from one or more of the other components of torque tube 24. Invarious embodiments, foot 112 may be coupled to radially inward surface114 using friction stir welding.

In various embodiments, both tube portion 100 and conical back-leg 104may be formed using non-additive manufacturing techniques. For example,tube portion 100 and conical back-leg 104 may be formed by forging,extrusion, casting, machining, stamping, subtractive manufacturing, orby welding conical back-leg 104 to tube portion 100. In variousembodiments, conical back-leg 104 may be formed by swaging or flaring anend of tube portion 100.

With reference to FIG. 2B, in various embodiments, tube portion 100 maybe formed using a first manufacturing process comprised of non-additivemanufacturing techniques and conical back-leg 104 may be formed on tubeportion 100 using a second manufacturing process that employs anadditive manufacturing technique. For example, tube portion 100 may beformed by forging, extrusion, casting, and/or machining, and conicalback-leg 104 may be formed by wire arc or electron beam additivemanufacturing. Forming conical back-leg 104 using additive manufacturingmay allow some or all of conical back-leg 104 to be formed using amaterial that is different from the material used to form one or more ofthe other components (e.g., tube portion 100 and/or stator splines 106)of torque tube 24. For example, in various embodiments, tube portion 100may be formed using Ti64 and conical back-leg 104 may be formed usingTi6242. Forming conical back-leg 104 using additive manufacturing alsoallows different portions of conical back-leg 104 to be formed usingdifferent materials. For example, a first portion of conical back-leg104 may comprise a material having a greater heat resistance (i.e.,higher melting point), tensile strength, and/or creep resistance ascompared to the material of a second portion of conical back-leg 104. Invarious embodiments, an end 107 of stator splines 106 may be tapered.End 107 may extend radially outward, along conical back-leg 104, at anangled orientation relative to centerline axis 102. In variousembodiments, the angle of end 107 relative to centerline axis 102 isequal to the angle of conical back-leg 104 relative to centerline axis102.

FIG. 4A illustrates a method 200 of making a hybrid torque tube for abrake assembly, in accordance with various embodiments. Method 200 maycomprise forming a tube portion having a centerline axis and a conicalback-leg extending radially outward from the tube portion (step 202) andforming stator splines on a radially outward surface of the tube portion(step 204). In various embodiments, step 202 includes forming, at least,the tube portion using a non-additive manufacturing technique, forexample, forging, extrusion, casting, machining, and step 204 includesforming the stator spline using an additive manufacturing technique, forexample, wire arc or electron beam additive manufacturing. In variousembodiments, a portion of at least one of the stator splines may behollow. In various embodiments, at least one of the stator splines maycomprise a lattice structure. In various embodiments, step 204 maycomprise forming at least one of the stator splines by depositing a basematerial and a coating over the base material.

With reference to FIG. 4B, in various embodiments, step 202 may compriseforming a tube portion using a first manufacturing process comprising anon-additive manufacturing technique, for example, forging, extrusion,casting, machining, (step 206), and forming a conical back-leg extendingfrom the tube portion using additive manufacturing, for example, usingwire arc or electron beam additive manufacturing (step 208). In variousembodiments, step 206 may comprise forming the tube portion using afirst material (e.g., a first metal alloy), and step 208 may compriseforming the conical back-leg using a second material (e.g., a secondmetal alloy) different from the first material.

With combined reference to FIGS. 4A and 4B, in various embodiments,method 200 may further comprise forming a foot extending from a radiallyinward surface of the tube portion using additive manufacturing (step210). In various embodiments, step 202 may comprise forming the tubeportion using a first material (e.g., a first metal alloy), and step 210may comprise forming the foot using a second material (e.g., a secondmetal alloy) different from the first material. In various embodiments,the second material may comprise a greater resistance to creep ascompared to the first material.

In various embodiments, method 200 may further include forming a flangeat an end of the tube portion opposite the conical back-leg (step 212).Step 212 may include forming the flange using additive manufacturing.Method 200 may further include forming a lip extending from a radiallyoutward end of the conical back-leg (step 214). Step 214 may includeforming the lip using additive manufacturing.

Benefits, other advantages, and solutions to problems have beendescribed herein with regard to specific embodiments. Furthermore, theconnecting lines shown in the various figures contained herein areintended to represent exemplary functional relationships and/or physicalcouplings between the various elements. It should be noted that manyalternative or additional functional relationships or physicalconnections may be present in a practical system. However, the benefits,advantages, solutions to problems, and any elements that may cause anybenefit, advantage, or solution to occur or become more pronounced arenot to be construed as critical, required, or essential features orelements of the disclosure.

The scope of the disclosure is accordingly to be limited by nothingother than the appended claims, in which reference to an element in thesingular is not intended to mean “one and only one” unless explicitly sostated, but rather “one or more.” It is to be understood that unlessspecifically stated otherwise, references to “a,” “an,” and/or “the” mayinclude one or more than one and that reference to an item in thesingular may also include the item in the plural. All ranges and ratiolimits disclosed herein may be combined.

Moreover, where a phrase similar to “at least one of A, B, and C” isused in the claims, it is intended that the phrase be interpreted tomean that A alone may be present in an embodiment, B alone may bepresent in an embodiment, C alone may be present in an embodiment, orthat any combination of the elements A, B and C may be present in asingle embodiment; for example, A and B, A and C, B and C, or A and Band C.

The steps recited in any of the method or process descriptions may beexecuted in any order and are not necessarily limited to the orderpresented. Furthermore, any reference to singular includes pluralembodiments, and any reference to more than one component or step mayinclude a singular embodiment or step. Elements and steps in the figuresare illustrated for simplicity and clarity and have not necessarily beenrendered according to any particular sequence. For example, steps thatmay be performed concurrently or in different order are illustrated inthe figures to help to improve understanding of embodiments of thepresent disclosure.

Any reference to attached, fixed, connected or the like may includepermanent, removable, temporary, partial, full and/or any other possibleattachment option. Additionally, any reference to without contact (orsimilar phrases) may also include reduced contact or minimal contact.Surface shading lines may be used throughout the figures to denotedifferent parts or areas but not necessarily to denote the same ordifferent materials. In some cases, reference coordinates may bespecific to each figure.

Systems, methods and apparatus are provided herein. In the detaileddescription herein, references to “one embodiment”, “an embodiment”,“various embodiments”, etc., indicate that the embodiment described mayinclude a particular feature, structure, or characteristic, but everyembodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed. After reading the description, it will be apparent to oneskilled in the relevant art(s) how to implement the disclosure inalternative embodiments.

Furthermore, no element, component, or method step in the presentdisclosure is intended to be dedicated to the public regardless ofwhether the element, component, or method step is explicitly recited inthe claims. No claim element is intended to invoke 35 U.S.C. 112(f)unless the element is expressly recited using the phrase “means for.” Asused herein, the terms “comprises”, “comprising”, or any other variationthereof, are intended to cover a non-exclusive inclusion, such that aprocess, method, article, or apparatus that comprises a list of elementsdoes not include only those elements but may include other elements notexpressly listed or inherent to such process, method, article, orapparatus.

1. A method of making a hybrid torque tube for a brake system,comprising: forming a tube portion having a centerline axis using afirst manufacturing process, the first manufacturing process comprisinga non-additive manufacturing technique; forming a conical back-legextending from the tube portion in a radially outward angled orientationrelative to the centerline axis; forming a stator spline on a radiallyoutward surface of the tube portion; and forming a foot extending from aradially inward surface of the tube portion, wherein at least one of theconical back-leg, the stator spline, or the foot is formed using asecond manufacturing process different from the first manufacturingprocess, the second manufacturing process comprising an additivemanufacturing technique.
 2. The method of claim 1, wherein a portion ofthe stator spline is hollow.
 3. The method of claim 1, wherein across-section of the stator spline comprises a lattice structure.
 4. Themethod of claim 1, further comprising: forming the tube portion using afirst metal alloy; and forming, at least, a portion of the conicalback-leg using a second metal alloy different from the first metalalloy.
 5. The method of claim 1, further comprising: forming the tubeportion using a first metal alloy; and forming the foot using a secondmetal alloy different from the first metal alloy.
 6. The method of claim5, wherein the second metal alloy comprises a greater resistance tocreep as compared to the first metal alloy.
 7. The method of claim 1,wherein forming the stator spline comprises depositing a base materialwith a coating located over the base material.
 8. A method of making ahybrid torque tube for a brake assembly, comprising: forming a tubeportion having a centerline axis using a first manufacturing process,the first manufacturing process comprising a non-additive manufacturingtechnique; and forming a conical back-leg extending from a first end ofthe tube portion; forming a flange at a second end of the tube portionopposite the first end of the tube portion; forming a foot extendingfrom a radially inward surface of the tube portion; and forming a statorspline on the tube portion, wherein at least one of the conicalback-leg, the flange, the foot, or the stator spline is formed using asecond manufacturing process, the second manufacturing processcomprising an additive manufacturing technique.
 9. The method of claim8, wherein the first manufacturing process comprises at least one offorging, extrusion, casting, machining, stamping, or subtractivemanufacturing.
 10. The method of claim 8, wherein at least one of theflange, the foot, or the stator spline is formed using the secondmanufacturing process, and wherein the conical back-leg is formed usingat least one of forging, extrusion, casting, machining, stamping,subtractive manufacturing, welding, or swaging.
 11. The method of claim8, wherein forming the stator spline comprises depositing a basematerial with a coating located over the base material.
 12. The methodof claim 8, wherein the tube portion comprises a first material and thefoot comprises a second material different from the first material. 13.The method of claim 8, wherein a portion of the stator spline is hollow.14. A hybrid torque tube for a brake assembly, the hybrid torque tubecomprising: a tube portion having a centerline axis, the tube portioncomprising a first metal alloy; a conical back-leg extending from thetube portion in a radially outward angled orientation relative to thecenterline axis; a stator spline formed on a radially outward surface ofthe tube portion; and a foot formed on a radially inward surface of thetube portion, wherein at least one of the conical back-leg, the statorspline, or the foot comprises a second metal alloy different from thefirst metal alloy.
 15. The hybrid torque tube of claim 14, wherein aportion of the stator spline is hollow.
 16. The hybrid torque tube ofclaim 14, wherein a portion of the stator spline comprises a latticestructure.
 17. The hybrid torque tube of claim 14, wherein the firstmetal alloy comprises a first nonferrous material, and wherein thesecond metal alloy comprises a second non-ferrous material differentfrom the first non-ferrous material, the second non-ferrous materialhaving a greater resistance to creep as compared to the firstnon-ferrous material.
 18. The hybrid torque tube of claim 17, whereinthe first metal alloy comprises, by weight, 6% aluminum, 4% vanadium, amaximum of 0.2% oxygen, a maximum of 0.25% iron, and at least 89%titanium, and wherein the second metal alloy comprises, by weight, 6%aluminum, 2% tin, 4% zirconium, 2% molybdenum, and at least 85%titanium.
 19. The hybrid torque tube of claim 14, wherein the firstmetal alloy comprises a first ferrous material, and wherein the secondmetal alloy comprises a second ferrous material different from the firstferrous material.
 20. The hybrid torque tube of claim 14, wherein an endof the stator spline proximate the conical back-leg is tapered.